crypto: arm/aes-ctr - fix NULL dereference in tail processing
authorArd Biesheuvel <ard.biesheuvel@linaro.org>
Tue, 13 Sep 2016 08:48:52 +0000 (09:48 +0100)
committerHerbert Xu <herbert@gondor.apana.org.au>
Tue, 13 Sep 2016 10:44:59 +0000 (18:44 +0800)
commitf82e90b28654804ab72881d577d87c3d5c65e2bc
tree1e7f834cc0b8e1275394ba1910b6622d20bf47c5
parentacdb04d0b36769b3e05990c488dc74d8b7ac8060
crypto: arm/aes-ctr - fix NULL dereference in tail processing

The AES-CTR glue code avoids calling into the blkcipher API for the
tail portion of the walk, by comparing the remainder of walk.nbytes
modulo AES_BLOCK_SIZE with the residual nbytes, and jumping straight
into the tail processing block if they are equal. This tail processing
block checks whether nbytes != 0, and does nothing otherwise.

However, in case of an allocation failure in the blkcipher layer, we
may enter this code with walk.nbytes == 0, while nbytes > 0. In this
case, we should not dereference the source and destination pointers,
since they may be NULL. So instead of checking for nbytes != 0, check
for (walk.nbytes % AES_BLOCK_SIZE) != 0, which implies the former in
non-error conditions.

Fixes: 86464859cc77 ("crypto: arm - AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions")
Cc: stable@vger.kernel.org
Reported-by: xiakaixu <xiakaixu@huawei.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
arch/arm/crypto/aes-ce-glue.c